Version of TCO? 1.9
Version of Warcraft 3? 1.26.0.6401
Is you Warcraft 3 settings on high? yes
Fatal on Ch.2 - sometimes. Always when activating the 5th Obelisk directly after 4th and fast. After reloading of the game and doing the quest @not so speedy@ - no fatal error.
Ch.3 - always. Tried to change quality settings, reload, tried to kill the last golems with direct attack one by one - still the same fatal error. Btw there were no fatal error in previous version of TCO - never on Ch.3. Maybe you've done some direct changes in the quest itself in the new version - dunno if it is possible - but could you copy all the triggers and code from the previous version (the last one before 1.9) and replace the new code with it?